Blasting cartridge



Aug- 6, 1929. A. w. HELMHoLTz Er AL 1,723,351

BLASTING CARTRIDGE Filed June 25, 1928 l Zz/efZ/U/fs Dm? f wel! d@ me Pme/M0225,

WISY/5715 al@ Patented Aug. 6, 1929i.

UNITED STATES.

1,723,351' PATENT OFFICE'.

ARTHUR W. HELMHOL'IZ AND DENT FEBRELL, OF HARRISBURG,. ILLINOIS, ASSIGNORS TO SAFETY MININGCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLI- N OIS.

Application led June 23,

This invention relates to improvements in blasting cartridges and particularly to the type of blasting cartridge which is refillable, having a releasable wall adapted to give Way at a predetermined pressure developed inside the cartridge to discharge the contents as When the cartridge is set 0H in blasting. It is preferable, although not necessary, that this improvement be employed With the type of cartridge containing a substance gaseous at ordinary temperature and pressure, confined in the cartridge under lpressure and preferably in liquid form, and having means' inside the cartridge for heating the contained substance above its critical temperature and subsequently vaporizing it in a manner to develop pressure suflicient to rupture or displace a wall thereof and discharge the expanding contents. I

This invention is illustrated as a modification of the invention disclosed and claimed in the applicants co-pending application, Serial No. 169,441, filed February 19, 1927, entitled Blasting Cartridges. The disclosure herein with the exception of the improved releasable Wall, which is described hereinafter in detail, is substantially the same as the disclosure of the co-pending application referred to and, therefore, the features of the cartridge not necessary to the understanding of the present invention are omitted. vThe cartridge disclosed in the copending application and that herein disclosed are adapted to operate with carbon dioxide gas as a blasting medium.

By referring to the applicants co-pending case it will be noted that the cartridge disclosed comprises a cylindrical container closed at one end with a rigid wall and having a. rupturable disk Wall at its opposite end held in position by a shear ring and cap. The shear ring is of hard metal and the rupturable wall is of relatively soft metal so that when predetermined pressure is developed in the cartridge the disk or rupturable wall is ruptured, the middle portion being forced outwardly as cut by the shear ring to permit the expanding gases to escape. The cartridge also comprises a heating element positioned in the container and connected electrically for detonation so as to discharge the cartridge.

The present invention has for its object to provide a novel form of releasable wall 1928.- Serial N0. 287,863.

cartridge releases has considerable bearing on the results obtained, and therefore, it is desirable to provide a simple, cheap and efficient -means for closing the discharge end of the cartridge, and one which will provide a sealed closure for the cartridge under ordinary conditions, but will displace to release the gases at substantially the desired pressure at all times, and to assure that no slow leakage of the gas is permitted While the pressure is building up internally before the predetermined pressure is reached.

Thepresent invention aims to provide all of the above advantages. Accordingly, the cartridge contemplated in this invention is designed to employ a liquefied medium such as carbon dioxide enclosed Within a rigid container, which container has a Wall in the form of a valve at, the discharge end. The valve is rigid and indestructable and, therefore, forms a inovable part of the container Vas a whole. The valve is composed of suitable metal and is designed to be held upon lts seat 1n a closed and gas-tight position While and after the container is filled with the liquefied blasting medium, by means of a collapsible metal tube of such thickness or buckling strength that when the blasting medium Within the rigid container is raised to a predetermined pressure lneans of artificial heat the tube supporting the valve seat will collapse or buckle or otherwise give way, allowing the valve to spring away from its seat and release the expanding blasting medium to escape into the drill hole in a coal seam or other body and thus exert a pressure sufficient to break down the material.

The various advantages are accomplished by means of the arrangement disclosed on the accompanying sheets of drawings,v in Which- Figure 1 is a side elevation of a blasting cartridge constructed in accordance with this invention; V

Figure 2 is a fragmentary View in cross section showing the discharge end of the The various novel features of the inven- Aing the closing cap 11 and electrical terminals 12 at one end and an end cap 13 with discharge ports 14 circumferentially arranged therein, all in a manner as set forth in the applicants copending application referred to. The rigid container 10 has a, reduced end 15 forming a nozzle, through which the gases are discharged. The outer surface of the reduced end 15 is threaded as at 17 in a manner to engage the threads 18 of the cap 13. Thecap is further provided with a plurality of discharge holes 14 through which the expanding gas is discharged in radial directions relative to the axis of the drill hole. The inner end of the reduced end 151' of the container is beveled as at 2() to form a seat for the valve or plug 2]. seated thereon. The valve 20 has a portion 22 correspondingly beveled adapted to snugly lit and engage the bevel 2O so as to provide a gas-tight seal vfor closing the discharge end of the container. An annular flange 23 is also provided on the valve plug for cooperating with the collapsible tube or sleeve 24 positioned between the valve plug and the end wall 25 of the cap 13. On the inner surface of the end wall 25 of the cap 13, centrally disposed, is an inwardly eX- tending circular protrusion 26 adapted to ,snugly fit the inner opening of the sleeve or tube 24. The valve also has a round projection 27 extending into the inside of the sleeve. The protrusions 26 and 27 cause the parts to be accurately centered to assure that the valve is properly positioned on the valve seat to maintain a gas-tight closure.

By referring to the modification in Figure 3 it will be noted that the reduced end 15 of the container -may be grooved as at 30, for receiving a gasket 31 of any suitable material. In this form the gasket renders it easier to attain a gas-tight seal, and is one in which the gasket is readilyrenewabla the parts being otherwise the same as those previously described.

From the above it will be noted that this invention provides a closing wall for cartridges which will accomplish all of the rcsults desired, and one which will maintain .a gastight seal under ordinary conditions sure is reached. The device is simple, cheap and eHicient and is readily assembled as when the cartridges are manufactured or being refilled. To assemble the cartridge it is merely necessary to introduce the sleeve and valve in proper relationship within the cap and to screw the capy on to the end of the reduced portion of the container. By this arrangement the pressure with which the valve is held upon its seat may be readily determined and varied at will by merely turning the cap, and it is not vnecessary that all of the sleeves be exactly the same length. Thispermissible' difference in the length of the sleeves eliminates the close workmanship and high degree of skill which is expensive and would be necessary where ezgact .measurements'are required for accomplishing the results sought. which the cartridge releases depends upon the strength of the sleeve, which, of course, may be Varied within very fine llmits by the thickness of the sleeve and the selectlon of the material from which the sleeve Vis made.

We claim:

The pressure at 1. A device of the character described comprising anrigid casing having an open end and containing a blasting medium under pressure and means for articially'heatingsaid medium, said open end having a valve seat, a valve against said seat and a cap enclosing said end and valve and a destructible means between said valve and cap/for holding said cap on. said sea t.

2. A releasable closing Wall comprising a valve seat, a surface spaced from and nor,- mally immovable relative to said seat, a valve plug on said seat and a destructible means between said surface and plug for maintaining said plug on said seat.

3. A releasable closing wall comprismg a valve seat, a surface spaced from and normally immovable relative to said seat, a

valve plug on said seat and a destructible .mally immovable relative to said seat, a

valve plug on said seat and a destructible tube between said' surface and plug for maintaining said lug on said seat and means on said surface and valve plug for centering said tube.

6. In a device of the character described, a container having an open end, a cap enclosing said end, said end having a valve seat, a valve on said seat and a destructible and renewable means between said valve and cap for holding said valve on said seat and ad-apted to be collapsed to release said valve from said seat at a predetermined pressure.

7 In a deviceof the character described, a container having an open end and a cap enclosing said end, and adjustable thereon, a valve seat on said end, and means between said cap and valve lplug for holding said plug on said seat, wlith variable pressure according to the position of said cap.

8. A releasable closingwall comprising a valve seat, a surface spaced from and normally immovable relative to said seat, a valve plug on said seat and a destructible and replaceable means between said surface and plug for maintaining said plug on said seat, said seat having a recess thereon with a gasket in s-aid recess.

9. In a device of the character described, a container having an open end with a valve seat on said end, a cap enclosing said end, releasable v-alve means between said cap and end comprising a valve plug, having a portion shaped to engage said valve seat, and a flange, a destructible and replaceable sleeve engaging said flange at one end and the end of said cap at its other end for holding said valve plug on'said seat.

10. In a device of the character described, a container having an open end with a valve seat onxsaid end, a cap enclosing said end, releasable valve means between said cap and end comprising a valve plug, having a portion shaped to engage said valve seat, and a flange, a destructible tube engaging said flange at one end, and the end of said cap at its other end for holding said valve plug on said seat and a projection on said valve plug and cap extending into said ltube for positioning said sleeve.

l1. In a blasting cartridge, the combination with a casing adapted to be charged With a liquefied gas and having meansvfor vaporizing the charge to increase the pressure within the casing and an outlet for the discharge of the vaporized charge, of a rel usable valve adapted to close said outlet 'and mpans for normally holding said valve in closing position and responsive to the attainment of a substantially predetermined pressure within the casing to permit said valve to open.

12. In a blasting cartridge of the type dcscribed, reusable valvular means for confining the charge within the cartridge and means for holding said valvular means closed until a substantially predetermined pressure is reached within the cartridge and then/ permitting said valvular means to open.

13. In 4a device of the character described, the combination with a casing adapted to bc charged with a liquefied gas and having means for vaporizing the charge to increase the pressure Within the casing and an outlet for the discharge of the vaporized ch-arge, of a valve seat for said outlet, a surface spaced from and normally immovable relative to said seat, a valve member on said seat and means between said surface and valve member for normally holding said member on said seat and responsive to the attainment of a substantially predetermined pressure within the casing to permit said valve member to move away from said seat and liberate the confined charge.

14. In a blasting cartridge, the combination with a casing adapted to be charged with a liquefied gas and having means for vaporizing the charge to increase the pressure within the casing and an outlet for the discharge of the vaporized charge, of a reusable valve adapted to close said outlet and means for normally holding said valve in closing position and responsive vtothe attainment of a substantially predetermined pressure within the casing to permit said valve to open, said means being incapable of returning said valve to closing position.

Signed at Duquoin, Illinois this 16th day of June, 1928.

ARTHUR W. HELMHOLTZ. DENT FERRELL. 

